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Ranges of transmission for square or sine wave into ferrite antenna...

Discussion in 'General Electronics Chat' started by Externet, Aug 8, 2017.

  1. Externet

    Externet Member

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    Hi.
    Which would propagate to a longer transmission distance, same power sine or square wave RF transmission signal fed to a ferrite loopstick ?

    What about same peak-to-peak amplitude for both waveforms ?
     
  2. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    A square wave gas many harmonics. (it will transmit on many different frequencies) So some of its power is going to the wrong frequency.
     
  3. RadioRon

    RadioRon Well-Known Member

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    If both the sine and square have the same total power, then the square wave will have less power at the fundamental and each harmonic frequency and assuming that we are talking only free space propagation, each component (fundamental or harmonic) will travel a shorter distance. So the sine wins.

    As for the second question... The total power of a square wave is twice that of the sine wave with the same peak amplitude, or +3 dB. However, the first harmonic of a square wave is down -4dB from the total power, so the first harmonic of the square wave is -1 dB lower than the sine wave. Also, the loop stick antenna is relatively high Q and has selectivity, so higher harmonics will probably not be well radiated. Considering these factors, the sine wave wins again.
     
    Last edited: Aug 8, 2017

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